div.overflow_1{
    width: 300px;
    height: 100px;
    border: 1px dashed aquamarine;
    
    /* 显示滚动条 */
    overflow: scroll;
}
div.overflow_2{
    width: 100px;
    height: 100px;
    border: 1px dashed red;
    font-size: 250%;
    /* overflow: hidden;隐藏 多余部分 */
    overflow: auto;
}
.box{
    width: 400px;
    height: 50px;
    border: 3px solid lawngreen;
    margin-top: 10px;
    background-color: peru;
}
.pos_static{
    position: static;
    background-color: pink;
}
.pos_relative{
    background-color: plum;
    position: relative;
    /* left: 10px; 右*/
    right: -50px;
    top: 20px;
    z-index: 100;
}
.pos_fixed{
    background-color: paleturquoise;
    position: fixed;
    top: 0px;
    right: 0px;
}
.pos_absolute{
    background-color: seagreen;
    position: absolute;
    top: 100px;
    left: 200px;
}

.menu:hover + .absolute_menu{
    display: block;
}
.absolute_menu{
    display: none;
    background-color: skyblue;
    position: absolute;
    top: 46px;
    left: 0px;
}
.pos_sticky{
    position: sticky;
    position: -webkit-sticky;
    background-color: chartreuse;
    bottom: 30px;
    margin-left: 400px;
}
.box_float{
    float: left;
    background-color: gold;
    margin-left: 20px;
}
.clf{
    clear: both;
}
li{
    float: left;
    width: 100px;
    border: 1px solid red ;
}